Organic acids (OAs) have been used as natural preservatives for food
products and as hygiene promoters to inhibit microbial growth, thereby improving the
freshness and shelf-life of food items. The impact of OAs on microbial growth makes it
an alternative to antibiotic growth promoters. The characteristic of inhibiting microbial
growth is a useful feature that has been recently used in poultry production. Organic
acids are chemically weak, and they modulate the beneficial competitive exclusion in
the gastrointestinal tract (GIT) and diminish the production of metabolites harmful to
the body by decreasing the proliferation and colonization of pathogenic bacteria in the
GIT. Further, they improve the ability of the intestinal wall to absorb nutrients by
improving the structure of the villi and the digestive secretions that lead to enhanced
absorption of proteins, carbohydrates, and minerals.
The use of 15g/kg of citric acid in broiler diets reduced the cecal total bacterial count
and Enterobacteriaceae by 62.26% and 80%, respectively, in comparison with control.
However, the same level of fumaric acid reduced the cecal total bacterial count and
Enterobacteriaceae by 88.63 and 78.57%, respectively. Similarly, the inclusion of
30g/kg of fumaric acid reduced the cecal total bacterial count and Enterobacteriaceae
by 95.84 and 88.57%, respectively. The immunity of broilers can thus be improved as a
normal consequence of all previously mentioned advantages. The use of 0.30 g/kg
blends of sorbic acid, fumaric acid, and thymol improved the spleen size of broiler
chickens by 50% when compared to control. Dietary inclusion of formic acid up to 5
and 10 g/kg significantly improved feed conversion ratio by 9.37 and 16.66% and
improved ileal digestibility of crude protein by 19.85 and 21.08%, respectively. This
chapter summarizes the possible modes of action of dietary OAs and their effects on
the growth and health of poultry.
Keywords: Antimicrobial activity, Nutrition, Organic acid types, Performance,
Poultry.